Friday, March 03, 2023

Meet the thriving stray dogs of Chernobyl

Sarah Knapton
Mar 04 2023

The nuclear ghost town of Pripyat, 2 kilometres from the Chernobyl Nuclear Power Plant, in a video marking the town's 50th anniversary in 2021.

Living amid the fallout of the world’s worst nuclear disaster may not seem like a sensible lifestyle choice, but the dogs of Chernobyl may have evolved to make it work, a study suggested.

Scientists have found that strays living in the exclusion zone of the Ukrainian disaster have developed distinct DNA and behaviour from other canines.

Since the nuclear catastrophe took place in April 1986, the area surrounding the nuclear power plant has largely been abandoned by humans.

But although radioactive contamination devastated wildlife populations there, some animals survived and continued to breed – including feral dogs, some of whom may have descended from domestic pets.

The team found that the strays had formed into packs, like wild dogs and wolves, but the groups were living close together, a behaviour not seen in undomesticated animals.

The dogs have been monitored by the Chernobyl Dog Research Initiative since 2017, and a new study of blood samples taken by the project team has shown that the animals were genetically different from other canines.

Now the team are planning to study the new genetic traits to see if any of the mutations is helping them to survive in the radiation zone.

Discovering how mammals evolve to live in harsh radiation environments could bring important insights into how to predict
 cancer in humans, or protect astronauts in the deadly radioactive environment of space.


SEAN GALLUP/GETTY IMAGES
Some animals, including dogs, survived and continued to breed long after Chernobyl was sealed off to humans.


Dr Elaine Ostrander, a geneticist from the National Human Genome Research Institute, part of the US National Institutes of Health (Nih), said: “We don’t yet know what, if any, genetic differences might allow dogs to survive in one versus another environment.

“Looking for changes in the DNA that have helped one versus the other population survive is the long-term goal of the study and one we are working towards now.

“We think that is an important experiment because those changes, if identified, would be helpful for understanding early events in cancer, help guide using therapies for diseases that are motivated by radiation exposure, and would suggest ways in which we can better protect ourselves from both accidental and natural radiation exposure.

“For instance, we know that space is a high radiation environment, and information from this study could help scientists design ideal protection for those spending significant time in space, as space exploration continues to expand.”

DIMITAR DILKOFF/GETTY IMAGES
Scientists hope that the genetic discovery could offer insights in preventing cancer in humans.

The Chernobyl disaster began on April 26 1986 with the explosion of reactor number four at the nuclear power plant causing an updraft of radioactivity which spread across Europe.

Two people died immediately and 29 within the coming days of acute radiation syndrome, while the United Nations estimated some 4000 more died from the fallout.

Many women also aborted their babies for fear they would be affected by radiation poisoning.


Some 300,000 people were evacuated from their homes and, in the aftermath, a 1600-square kilometre exclusion zone was set up around the site.

DIMITAR DILKOFF/GETTY IMAGES
The stray dogs have been monitored by the Chernobyl Dog Research Initiative since 1997.

However, in recent years, researchers have found that closing off the land to humans has allowed wildlife to flourish, with the area now a haven for lynx, bison, brown bear, wolves, boar and deer as well as 60 rare plant species.

The Chernobyl Exclusion Zone currently represents the third-largest nature reserve in mainland Europe and is often considered an accidental experiment in rewilding.

Previous studies showed that exposure to radiation speeds up the genetic mutation rate among plants, with some species evolving new chemistry that makes them more resistant to radiation damage and protects their DNA.

Scientists have pointed out that in the past when early plants were evolving, levels of natural radiation on Earth were far higher than now, so species may be able to switch on dormant traits to survive.

However, it was unknown whether the same protective adaptations would be seen in larger animals.

The new study was based on 302 free-roaming dogs living in the exclusion zone, which were found to have different genetic make-ups depending on how much radiation they were exposed to.

The Nih team is now planning to study the genetic changes to find out whether they are helping the dogs to survive.

The research was published in the journal Science Advances

READ MORE:


The Chernobyl Nuclear Disaster Created Genetically Mutant Dogs


Maddie Bender
Fri, March 3, 2023

Photo Illustration by Luis G. Rendon/The Daily Beast/Pixabay

Roughly 350,000 people evacuated during the 1986 disaster at the Chernobyl Nuclear Power Plant in 1986, leaving their lives and belongings behind to flee the worst nuclear disaster in history. Facets of residents’ lives left behind but often unmentioned are their pets, which evacuees were forbidden to retrieve. Despite the high levels of radiation in the Chernobyl Exclusion Zone, many of these animals survived, and their descendants can be found in and around the region today.

Prancer, one of these dogs, got her name from a dance she does whenever she greets Tim Mousseau’s research team. Mousseau, a biology researcher at the University of South Carolina, has studied the effects of radiation on living organisms in sites like Chernobyl and Fukushima for decades. Usually, however, his subjects are a lot smaller, potentially a result of the extremely harsh conditions created by nuclear radiation.

“These are dogs. You can't help but love them and develop relationships with them,” he told The Daily Beast. “We think about bringing them home with us every time we go.”

Dog Genes Hold More Secrets About Humans Than You Think

Even in conditions that drastically limit their lifespan—Mousseau said most of the Chernobyl canines only live to three—the dogs have found a way to thrive. Locals and an increasing number of dark tourists feed the dogs resulting in a surge in the canines’ population that have driven nonprofits and researchers to regularly provide veterinary care, and spay and neuter as many dogs as they can. Over the course of three years, Mousseau has collected hundreds of blood samples from the dogs as part of these efforts.

The dogs’ blood contained an incredibly rare opportunity: a glimpse into how life prevails even under unnaturally harsh conditions. When Mousseau came to National Human Genome Research Institute geneticist Elaine Ostrander to analyze nearly 300 of these blood samples, she wasn’t about to let the chance slip by.

“I said, ‘Me, me, me, me, me,’” she told The Daily Beast. “It's such an extraordinary opportunity, and it does have implications for human health and biology.”

The Mystery of Chernobyl’s Black Frogs

Mousseau and Ostrander’s team published genetic sequencing results from the Chernobyl dogs on March 3 in the journal Science Advances. According to the authors, the study represents “the first genetic analysis of domestic dogs affected by a nuclear disaster,” providing a baseline to measure the impact of prolonged radiation exposure on an animal’s genetic health.

The radiation in Chernobyl City and near the power plant breaks the pooches’ DNA strands. Their cells try to repair it, but errors often occur. DNA gets deleted, spontaneously added, or switched around willy-nilly. Understanding how the Chernobyl dogs are able to survive in spite of this constant assault could inform a field like cancer treatment, since incorrectly repaired DNA is often found in cancer cells, Ostrander said.

“These dogs are surviving generation after generation, they’re fertile, they're carrying out all their bodily functions, and they even have behavioral relationships with people in the area—they're doing all the dog stuff they're supposed to be doing,” Ostrander said. “What's allowed them to overcome [the radiation]? From the viewpoint of someone at the National Institutes of Health, we really care about that.”

Russian Troops Left Mines and Fires Around Chernobyl in ‘Nightmare’ Scenario

During visits to the Exclusion Zone, Mousseau and others have noticed dogs living both in Chernobyl City and in and around the nuclear power plant—the latter of which is striking, given the area’s high, ongoing levels of radioactive contamination. But it was not known how closely these two populations were related, and additionally, how genetically similar they were to dogs in a nearby village.

As it turned out, both were genetically distinct—from a nearby village dog population and from each other. The next step, which the researchers are already diving into, is to start to isolate the genetic regions that make the Chernobyl dogs different. It’s all speculation at the moment, but Mousseau and Ostrandar both have theories.

For his part, Mousseau has studied an assortment of flora and fauna in radiation zones and found that some species of birds have safety mechanisms in their genes that protect them from the worst effects of the radiation. Might the dogs living near the power plant have such molecular failsafes, too?

Roving Packs of Robot Dogs Are Coming to the Moon

Now that the researchers have a baseline for these dogs, they are able to isolate genetic differences that aren’t just due to the quirks of the populations. Any disparate finding could improve the dogs’ ability to survive in their environment. For instance, if the Chernobyl dogs have genes encoding shorter fur than others nearby, it might mean they don’t hold onto as much radioactive dust in their coats. Or, if they have more genes relating to processing scents, it might mean the dogs can smell without putting their noses to the radioactive soil.

“In terms of looking at the genome, this is one of the most exciting projects ever,” Ostrander said.

But Russia’s invasion of Ukraine has complicated the research efforts: The last time Mousseau visited the region, the Crimea Bridge was bombed. Currently, his team sends about 800 kilos of food to the dogs every week, and the nonprofit Clean Futures Fund supports on-the-ground care for the animals.

“We hope that this research will shine a light on the situation in Ukraine to a broader audience,” Mousseau said. “We should all be concerned about the care of animals, even if they're stuck in a place like Chernobyl, in a war zone.”

Can the dogs of Chernobyl teach us new tricks on survival?

Scientists are studying hundreds of dogs at the Chernobyl disaster site that have managed to survive in extremely harsh conditions

By LAURA UNGAR - 
AP Science Writer
Mar 3, 2023 

This photo taken by Timothy Mousseau shows dogs in the Chernobyl area of Ukraine on Oct. 3, 2022. More than 35 years after the world's worst nuclear accident, the dogs of Chernobyl roam among decaying, abandoned buildings in and around the closed plant – somehow still able to find food, breed and survive.


This photo provided by Timothy Mousseau in Feb. 2023 shows a dog in the Chernobyl area of Ukraine. More than 35 years after the world's worst nuclear accident, the dogs of Chernobyl roam among decaying, abandoned buildings in and around the closed plant – somehow still able to find food, breed and survive.

More than 35 years after the world's worst nuclear accident, the dogs of Chernobyl roam among decaying, abandoned buildings in and around the closed plant – somehow still able to find food, breed and survive.

Scientists hope that studying these dogs can teach humans new tricks about how to live in the harshest, most degraded environments, too.

They published the first of what they hope will be many genetics studies on Friday in the journal Science Advances, focusing on 302 free-roaming dogs living in an officially designated “exclusion zone” around the disaster site. They identified populations whose differing levels of radiation exposure may have made them genetically distinct from one another and other dogs worldwide.

“We've had this golden opportunity” to lay the groundwork for answering a crucial question: “How do you survive in a hostile environment like this for 15 generations?” said geneticist Elaine Ostrander of the National Human Genome Research Institute, one of the study’s many autho

Fellow author Tim Mousseau, professor of biological sciences at the University of South Carolina, said the dogs “provide an incredible tool to look at the impacts of this kind of a setting” on mammals overall.

Chernobyl’s environment is singularly brutal. On April 26, 1986, an explosion and fire at the Ukraine power plant caused radioactive fallout to spew into the atmosphere. Thirty workers were killed in the immediate aftermath while the long-term death toll from radiation poisoning is estimated to eventually number in the thousands.

Researchers say most of the dogs they are studying appear to be descendants of pets that residents were forced to leave behind when they evacuated the area.

Mousseau has been working in the Chernobyl region since the late 1990s and began collecting blood from the dogs around 2017. Some of the dogs live in the power plant, a dystopian, industrial setting. Others are about 9 miles (15 kilometers) or 28 miles (45 kilometers) away.

At first, Ostrander said, they thought the dogs might have intermingled so much over time that they’d be much the same. But through DNA, they could readily identify dogs living in areas of high, low and medium levels of radiation exposure.

“That was a huge milestone for us," said Ostrander. “And what’s surprising is we can even identify families” – about 15 different ones.

Now researchers can begin to look for alterations in the DNA.

“We can compare them and we can say: OK, what’s different, what’s changed, what’s mutated, what’s evolved, what helps you, what hurts you at the DNA level?” Ostrander said. This will involve separating non-consequential DNA changes from purposeful ones.

Scientists said the research could have wide applications, providing insights about how animals and humans can live now and in the future in regions of the world under “continuous environmental assault” – and in the high-radiation environment of space.

Dr. Kari Ekenstedt, a veterinarian who teaches at Purdue University and was not involved in the study, said it's a first step toward answering important questions about how constant exposure to higher levels of radiation affects large mammals. For example, she said, “Is it going to be changing their genomes at a rapid rate?”

Researchers have already started on the follow-up research, which will mean more time with the dogs at the site about 60 miles (100 kilometers) from Kyiv. Mousseau said he and his colleagues were there most recently last October and didn’t see any war-related activity. Mousseau said the team has grown close to some dogs, naming one Prancer because she excitedly prances around when she sees people.

“Even though they’re wild, they still very much enjoy human interaction," he said, “Especially when there’s food involved.” 

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